The game is a direct port from the Nintendo DS and Sony PSP, and throwback to the top-down perspective of the first two GTA games.
It's especially notable that the game costs $9.99. That's a little bit steep for an iPhone game, but it's much cheaper than the game was on the DS or PSP, where it debuted at $34.99 and $39.99, respectively. The touchscreen controls work well and the level of graphical quality lands between that of the Nintendo DS and PSP versions.
The reception has been positive so far. As we're writing this, the game has 40 ratings and an average of 4.5 stars. App Store user Puese gave it five stars and said: "The polish on this is over the top. We have come a long way from only having snake on your phone as a game." However, marcosrdz gave it only one star, saying that it crashes a few seconds after displaying the terms of service screen. Some players say that it lacks a few minor features of the DS version — for example, pedestrian speech has been removed, presumably to reduce the size of the download.
Our experience with Chinatown Wars has been good, too; the game runs smoothly, and while the touchscreen controls aren't quite as comfortable as those on the DS or PSP, they're more than good enough.
Here's a video of the game in motion courtesy of Touch Arcade.